Detective Taek-rok gets a prank call. The unknown caller says something he cannot ignore.

Taek-rok is framed for murder and gets interrogated. He delves into the past cases he undertook.

Taekrok realises the mistake he made in the past. The caller gives orders that cause Taekrok to become suspicious of everyone around him.

Taekrok entrusts the blackmailer's information to Jinhan then gets a clue about the blackmailer's identity.

Seong-a and Gyeong-chan decide to help Taek-rok, who realizes the blackmailer's target is not him.

Taek-rok chases a man who has a key to the truth. However, the man resists.

Taek-rok has conflicts with his team leader Yeon Ju-hyun. Seong-a struggles in a juvenile theft probe.

Seong-a gets injured, and Taek-rok tries to uncover the truth. Meanwhile, Gyeong-chan doubts Taek-rok.

Despite Taek-rok's caution, Seong-a pursues probing and ends up getting injured. Meanwhile, Taek-rok meets his old colleague Do-hyung.

Taek-rok reaches out to Lee Young-ho, who is jealous of Do-hyung. Taek-rok stops Seong-a from uncovering the arson case and discovering his secret.

Taek-rok manages to identify an unknown skilled armed force with the help of Team Leader Han's testimony and devises a plan to lure them out.

Despite feeling helpless in the face of his enemies, Taek-rok finds motivation in the determination of those around him and continues his pursuit.

Taek-rok faces his past that he has been shunning and delves into the root of the problem. He is determined to protect his loved ones at all costs.

After successfully apprehending some members of the crime organisation, Taek-rok closes in on the rest of the group.